Golf club designs have been very diverse in order to achieve various performance objectives within the game of golf. For example, driver type golf clubs have been designed to maximize the distance of a golf shot, especially when the golf ball is sitting in a good lie on top of a tee. On the other side of the spectrum, putter type golf clubs have been designed to maximize accuracy for short precise shots on the putting green in order to get the golf ball into the cup. Mixed in between driver type golf clubs and putter type golf clubs are numerous other club designs such as fairway wood type golf clubs, hybrid type golf clubs, iron type golf clubs, and even wedge type golf clubs. Each of the above mentioned types of golf clubs have specific design objectives which achieve the correct balance of distance and accuracy for the specific types of golf shot that is desired.
When a golfer is not utilizing a tee, the various types of landing spots of a golf ball will generally greatly affect the club selection as well as finding the correct balance between distance and accuracy. These golf shots not executed from a tee box will vary from one another depending on the surface conditions from which the golf ball needs to be struck. Regardless of which kind of surface condition a golfer is faced with, these various surface conditions all tend to affect the performance of a golf club as the club attempts to strike a golf ball resting on such a surface. In one scenario, the golf ball could be sitting in a rough area containing high and tall grass creating a high coefficient of friction between the grass and the golf club. This increased coefficient of friction dramatically reduces the speed of a golf club as it comes into contact with the golf ball, resulting in slower clubhead speed as the club head. In fact, even if a golf ball is not sitting in tall grass with a high coefficient friction, a golf ball resting on any other grassy surface will offer up some resistance when the golf club comes into contact with the grassy ground. These types of various surface conditions could very well reduce the speed of the golf swing through varying degrees of coefficient of friction and may even deflect the potential direction of travel of a golf club from its desired path. This deflection, although generally minimal, could significantly impair the accuracy of a golf shot because it causes the golf club to be pointed away from the intended target line during impact.
This frictional interaction between the golf club and the ground may generally be known as “turf interaction” within the golf industry. Although certain particular situations will require an increased turf interaction between the golf club and the ground, it is generally desirable to minimize the turf interaction between the golf club and the ground. In order to minimize the amount of energy lost due to frictional turf interaction when the golf club interacts with the ground, various shapes and sizes of the golf club sole has been developed to reduce the contact area; hence reducing the coefficient of friction between the golf club and the ground. These methods of merely altering sole shape, although capable of slightly improving the turf interaction, still leave a very large sole profile coming into contact with the ground, making them unsatisfactory in terms of truly minimizing turf interaction.
U.S. Pat. No. 1,669,482 to Miller titled Golf Club ('482 patent) addresses the above shortcomings by disclosing an improved methodology to truly minimize turf interaction while reducing coefficient of friction and energy loss between a golf ball and the ground. More specifically, the '482 patent discloses a club having a rib or heel at the sole for driving a golf ball which shall have means on the bottom face or sole of its head to engage the turf during a part of the sole of the club. The head according to the '482 patent will generally be guided in the direction of intended flight of the ball and will follow the same a short distance with the result that the ball is driven true and straight and has imparted thereto a spin that increase the rolling action thereof upon landing from its flight.
Alternatively, U.S. Pat. No. 4,332,388 to Crow titled Golf Club Head ('388 patent) discloses an alternative means to address the above mentioned shortcomings utilizing a pair of spaced parallel runners. More specifically, the '388 patent discloses a club with a sole plate, wherein the sole plate has a pair of spaced parallel runners projecting downwardly and extending from front to rear across the full width of the plate. The runners are substantially semicircular in cross section and are quite large compared to ribbed or grooved structures which have been used.
Although both the '482 patent and the '388 patent are capable of reducing the coefficient of friction and energy loss of a golf club as it comes into contact with a ground, the sole profiles are only suitable for use when the ground is completely flat and without any undulations. Golfers who play golf may attest to the fact that golf courses are generally filled with uneven landscaping and uneven undulations, making the need to execute a golf shot from an uneven lie just as important as the ability to do so from a completely flat lie. The '482 patent and the '388 patent, with their singular rib or pair of parallel runners, are unable to reduce the coefficient of friction and energy loss when a golfer needs to hit a golf shot from an uneven lie as their sole rib or runners only run in one plane.
In order to address the need of a golfer to execute a golf shot that also minimizes turf interaction for uneven lies, it may be desirable to have a golf club that contain a sole profile that contains a plurality of rails with some being at different angles to allow the club head to compensate for such uneven lies. It may also be desirable to utilize such a lie angle adjustment independently of the slope of the ground, in order to provide a golf club head that's capable of sitting upright or flat irrespective of the lie. Finally, it may also be desirable for such a club to be paired with an adjustable hosel to allow for ease of adjustment of the lie angle, face angle, or any other angles necessary to take full advantage of the sole profile.
It can be seen from the above that there is a need for a golf club that is capable of improving turf interaction with the ground regardless of whether the golf ball sits on a perfectly flat lie or an uneven lie. Hence it can also be seen, there is tremendous advantage in the field for a golf club that contains a sole profile that allow for the golf club to sit properly at different lie angles and yielding minimal turf interaction at different lie angles. More specifically, there is a need in the field for a golf club containing a plurality of rails on the sole that are angled in such a way to allow for the golf club head to have a change in lie angle when different combination of the plurality of rails are in contact with the ground.